Italy is taking a radical step toward reducing pollution in urban areas by way of the world's first "vertical forest." Bosco Verticale, by Boeri Studio and architects Stefano Boeri, Gianandrea Barreca and Giovanni La Varra, is a set of apartment complexes in Milan that will feature 17,000 trees and plants covering residents' balconies. "I think this is a representation of [Milan's] broader green space and biodiversity plan," said Daniel Handeen, research fellow at the Center for Sustainable Building Research at the University of Minnesota. Hardeen noted that the buildings are meant to be a billboard for increasing sustainability in urban areas. Minnesota's cold weather prevents a "vertical forest" from being built, Handeen said, but the Target Center's green roof is making similar strides in sustainability.